Method of accurately and precisely constructing artificial dentures

ABSTRACT

Artificial dentures are accurately and precisely constructed using a dental articulator which is rigid, nonyielding and which stores, preserves and makes available every determinant required to build accurate intercuspation of teeth. A unique transparent tooth-setting guide which allows rapid &#39;&#39;&#39;&#39;see-through&#39;&#39;&#39;&#39; mounting of the casts, indicates the size of the teeth suitable for the case and guides the placement of the teeth. With the dental articulator and transparent tooth-setting guides dentures are constructed by (1) establishing the occlusal plane on the biterim or on the teeth, (2) mounting the lower cast on the articulator in a manner to preserve the plane of occlusion, the mounting making use of the transparent tooth setting guide, (3) mounting the tooth-setting guide to the lower cast, (4) mounting the lower cast to the articulator, (5) mounting the upper cast and (6) arranging the teeth in the casts.

Unite tates atent i 1 Jankelson METHOD OF ACCURATELY AND PRECISELYCONSTRUCTING ARTIFICIAL DENTURES [76] Inventor: Bernard Jankelson, 1451Medical- Dental Bldg., Seattle, Wash.

[22] Filed: Feb. 22, 1971 [21] App]. No.: 117,542

Primary Examiner-Robert Peshock Att0rneySeed, Berry & Dowrey ABSTRACTArtificial dentures are accurately and precisely constructed using adental articulator which is rigid, nonyielding and which stores,preserves and makes available every determinant required to buildaccurate intercuspation of teeth. A unique transparent toothsettingguide which allows rapid see-through mounting of the casts, indicatesthe size of the teeth suitable for the case and guides the placement ofthe teeth. With the dental articulator and transparent toothsettingguides dentures are constructed by (1) establishing the occlusal planeon the biterim or on the teeth, (2) mounting the lower cast on thearticulator in a manner to preserve the plane of occlusion, the mountingmaking use of the transparent tooth setting guide, (3) mounting thetooth-setting guide to the lower cast, (4) mounting the lower cast tothe articulator, (5) mounting the upper cast and (6) arranging the teethin the casts.

v 9 Claims, 8 Drawing Figures PATENTEUMARZYIQYS FIG 6 I INVENTOR-BERNARD JANK ELSON ATTORNEYS METHOD OF ACCURATELY AND PRECISELYCONSTRUCTING ARTIFICIAL DENTURES BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to a method of accurately andprecisely constructing artificial dentures and to means foraccomplishing such.

2. Prior Art Relating to the Disclosure In the construction ofartificial dentures, biterims representing the lost teeth and tissuesare mounted on a base plate which is generally contoured accurately tothe denture area. The biterims are formed generally from a heatsoftenable material such as a high melting point wax. To obtain theapproximate occlusal plane of the biterim parallel to the orbital plane,metal arcs are used. The biterims then are generally constructed onplaster casts of the human jaws and mounted on a dental articulatorwhose function is to furnish a relationship of the jaws of the patientupon which artificial teeth can be arranged within practical limits ofaccuracy. Artificial teeth are then set to their proper position on thebase plate. During the entire process any errors introduced in the castsor their mountings by move ment of the articulator or in mounting of theteeth or inaccuracy of the occlusal plane in relation to anatomicalstructure destroys the proper relationship of the dentures causingimproper fitting, improper mastication or other problems.

SUMMARY OF THE INVENTION This invention relates to a method ofaccurately and precisely constructing artificial dentures making use ofa unique dental articulator and unique tooth-setting guide. The dentalarticulator used has a posterior post of rugged construction. Lower andupper arms extend at right angles from the posterior post parallel toeach other with the upper arm hinged for vertical movement about itsconnection to the posterior post. The arms are of rugged construction toinsure maintenance of the vertical height between them under normal handpressures. The hinge is constructed to prevent any side play which couldcause loss of the precise horizontal or vertical position. In makingmodels of the upper and lower jaws of the patient the lower biterim issecured to a transparent tooth-setting guide in a manner so as toprevent any movement of the guide relative to the biterim in ahorizontal or vertical direction. The toothsetting guide establishes (1the horizontal plane of occlusion, (2) the anterior-posterior plane ofocculsion and (3) the size of the teeth. After constructing the biterimon dental stone the tooth-setting guide is used to mount teeth in thecase and to guide placement of the teeth.

It is a primary object of this invention to provide a method ofaccurately and precisely constructing artificial dentures, (2) toprovide a transparent tooth-setting guide available for reference to theocclusal plane as transferred from the mouth and (3) to provide atransparent tooth-setting guide which indicates the size of teeth properto the case.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 6 illustrate certain of thesteps employed in constructing artificial dentures by the method of thisinvention using a unique dental articulator and unique tooth-settingguide; and

FIG. 7 is a plan view of the transparent tooth-setting guide of thisinvention; and

FIG. 8 is a partial cross-section view through the tooth-setting guideillustrating a modified way of securing the stem to the guide body.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The dental articulator shown inFIGS. 2 through 6 is a rigid, non-yielding precision instrument whichstores, preserves and makes available every determinant required tobuild accurate intercuspation of teeth. The vertical height andhorizontal or centric" positions are held exactly as registered in themouth without approximation or guesswork. If the horizontal and verticaldimensions taken from the mouth and transferred to the articulatorchange on the articulator, both the vertical and horizontal positionsare thrown off with the result that the teeth are improperly set, and donot intercuspate precisely. This causes a deleterious function of themusculature of the mouth. The articulator must be able to transmitinformation accurately and without change so that teeth will be set tocertain preset positions. Dental articulators used in the past have notbeen capable of doing this.

The dental articulator employed in the method of this invention andshown in FIGS. 2 to 6 includes an upright posterior post 10 of ruggedconstruction from which parallel arms 11 and 12 extend. The lower arm 12is rigidly fixed to the lower end of the post 10. The upper arm ishinged for vertical movement about a hinge connection 13 to the upperend of the posterior post 10. Both the upper and lower arms are ofrugged construction so that the vertical height between them cannot bevaried by ordinary hand pressures even when the anterior post 15 isremoved.

The articulator utilizes a double stop system which completelyeliminates vertical height collaps and prevents horizontal side play. Anadjustable stop 14 contacts the upper surface of the posterior post 10and stops the upper arm at a predetermined position. The anterior post15 is removable as shown also can be used to set and adjust the verticalheight between the upper and lower arms. The anterior and posteriorstops work together as a single stop or they can work independently astwo separate stops. In practice, when the anterior pin is removed, theposterior pin 14 acts as a stop to insure precise, maintenance of thevertical height. The hinge connection 13 of the upper arm to theposterior post 10 is so constructed to prevent any side play which couldcause loss of the precise horizontal or centric position. Square ornon-round mounting holes 16 and 17 are provided in the arms 11 and 12for mounting of cast retainers 18 or the transparent toothsetting guide20 to be described.

The transparent tooth-setting guide 20 is shown in plan view in FIG. 7and comprises an arcuate body 21 of rigid construction to which avertical stem 24 is attached. The vertical stem should be of a form toprevent rotation thereof relative to the arms of the articulator wheninserted therein. The stem, as illustrated in the drawings, is squareand adapted to be received in the openings 16 or 17 in the arms of thearticulator.

The stem is also secured to the guide body in a manner to preventrotation of the guide body relative to the stem. This can beaccomplished in one way by making a square opening in the guide bodythrough which the square stem is inserted. The arcuate body has acurvature of predetermined dimensions and is generally referenced to thesame curvature as metal arcs used to form the occlusal plane of thebiterims. The transparent tooth-setting guide performs at least threefunctions: (1 establishes the horizontal plane of occlusion, (2)establishes the anterior-posterior plane of occlusion, (3) establishesthe size of the teeth suitable for the particular case and (4) providesa physical structure against which to set the teeth to correctpositions. The tooth-setting guide is suitably made of a structuralplastic which is clear and sufficiently rigid that it cannot bedistorted under reasonable pressures encountered during construction ofdentures. The arcuate body 21 has a number of openings 22 therethroughwhich are large enough to allow the dentist or technician mounting teethon the base plate to insert an instrument through the arcuate body 21 tocorrectly position teeth on the cast. Three sets of programmed holes 23are used for securing the arc body to the biterims. The anterior set ofholes also indicates the size of teeth appropriate to the case. Theparticular midline hole of the anterior set in the transparent guidebody 21 that is over the anterior edge of the lower biterim indicatesthe size of teeth appropriate to the case. If the most anterior hole isdirectly over the edge of the biterim it indicates that the mouth islarge and that approximately 34 mm posteriors and accordingly largeanteriors are indicated. The next hole posteriorily of the first holeindicates 32 mm posteriors, the next mm posteriors and the last 28 mmposteriors. The stem 24 of the transparent guide 20 has two or moreadjustable thumb screws 25 secured thereto to secure the guide to theupper and lower arms of the articulator and fix it to a particularvertical height.

In many cases it is necessary to make a correction in the occlusal planeafter the teeth are set in the casts. If the occlusal plane is raisedvertically, for example, to adjust to a necessary change in the heightof the mandibular incisors or other teeth without change in the tilt orangle of the guide body relative to the horizontal plane of occlusion,problems in fitting may occur. To avoid this the stem 24 is hinged tothe guide body 21 by a ball and socket arrangement 33 (see FIG. 8) orother suitable means so that the angle of the guide body can be changedrelative to an established horizontal plane of occlusion.

METHOD OF CONSTRUCTING DENTURES PRECISELY AND ACCURATELY USING THETOOTH-SETTING GUIDE AND DENTAL ARTICULATOR In constructing dentures theupper and/or lower biterims, made in a conventional manner are formed towhatever landmarks the technician or dentist may prefer. A preferredmethod of forming the upper or lower biterims in wax is to firstdescribe a line on the anterior aspect of the lower biterim about 1 mmabove the lower lip and parallel to the orbital plane across the pupilsof the eyes. The anterior-posterior occlusal plane is established bydividing the height of each retromolar pad into three parts, drawing aline across the wax impression at the height of the upper third andextending the line over the base plate onto the outside of the lingualflange. The base plate is then placed on a cast and a pencil line drawnacross the base of the cast to join the line from the base plate. Metalarcs of a predetermined curvature, conventionally used, are then used tomelt the wax of the biterim down to form the occlusal plane. Theanterior aspect of the wax biterim is melted down to the orbitalreference plane by heating the are, pressing the heated arc onto the waxbiterim and directing pressure to form the wax down to described orbitalreference line. This establishes the occlusal plane of the biterimparallel to the orbital plane. The cast is then turned around and thewax forming'arc is used to melt the biterim of each side down to theheight of the line previously described on the outer surface of thelingual flange. By the process described the plane of occlusion on thelower biterim is established. The centric registration can be obtainedin the mouth by imprinting an upper wax biterim against the lower in aconventional manner.

After obtaining the centric registration in the mouth of the patient thelower east is ready to be mounted on the articulator and should bemounted such that the plane of occlusion is preserved for referencethroughout construction of the case. The transparent tooth-setting guideis available for reference to the occlusal plane as transferred from themouth. A transparent tooth-setting guide having an arc conforming tothat of the metal are used in forming the occlusal plane on the biterimis used. Wax biterims have a way of being destroyed during setting ofthe teeth. By forming a reference point with the transparenttooth-setting guide against which the teeth are to be set it does notmatter whether the wax biterims are destroyed or not.

The transparent tooth-setting guide 21 which matches the metal are usedto form the occlusal plane is secured over the biterim 29 as shown inFIG. 1. The posterior edge of the guide is matched to the mark acrossthe base of the cast and the midline of the arc is matched to themidline mark on the biterim 29. The tooth-setting guide 20 is pinned tothe biterim 29 by inserting pins 26 through the holes 23 in the arcuatebody 21 of the guide. Spring clamps 27 or other suitable means are usedto hold the biterim 29 firmly to the lower surface of the arc body 21.The pin-and-clamp combination holds the orientation'firmly duringarticulation mounting. The pins hold the biterim firmly to the arc in ahorizontal position while the clamps hold the arc body firmly in avertical position and prevent it from dropping away. The tooth-settingguide secured to the biterim 29 in the manner described stores thefollowing in the guide: (1) the horizontal or orbital plane ofocclusion, (2) the anterior-posterior plane of occlusion and (3) thesize of the teeth appropriate to the case. This information stored inthe tooth-setting guide is then ready for transfer to the articulator sothat it can be referred to at any time during arrangement of the teetheven though the wax biterim may have been cut away.

The lower biterim mounted as shown in FIG. 1 to the guide 20 is securedto the upper arm of the articulator as shown in FIG. 2. The stem 24 ofthe guide is inserted through the opening 16 in the upper arm 11 of thearticulator and the thumb screws 25 adjusted so that there is a smallamount of space between the base 28 and the cast retainer 18 secured tothe lower arm 12 of the articulator. The thumb screws 25 are tightenedonce the position is established so that the vertical height of theguide cannot change. The anterior pin 15 is then bolted above the upperarm of the articulator as shown in FIG. 2 so that when the upper arm islayed back it will support the upper articulator arm against the bench.A casting material 30 such as dental stone is then piled over the lowerarm 12 of the articulator and cast retainer 18. The upper arm is thenclosed to embed the base plate and biterim into the casting material onthe lower arm, as shown in FIG. 3. A flexible plastic strip cut to fitaround interfering articulator parts may be used to form the castingmaterial neatly by wrapping it around the cast and the mounting. Thecasting material is then allowed to harden. The transparent guide isthen removed from the wax biterim by pulling off the pins and pullingout the clamps. It is desirable at this time to transfer the facialcontours of the biterim to the tooth-setting guide by marking around theoutside of the biterim onto the lower surface of the body 21 of thetooth-setting guide with a suitable marking pen or grease pencil so thatthe technician or dentist will later be able to look down through thetransparent guide and accurately set the facial surfaces of themandibular teeth to the line so marked and thus duplicate the contour ofthe biterim. The tooth-setting guide, once marked, is removed from thearticulator.

The upper cast is mounted by securing the maxillary bite rim 31 to thelower biterim with wax or other material as shown in FIG. 4. The castmay be more securely fastened together by heating the jaws of a springclamp or staple and embedding them to insure that there will be nodislodgement during mounting. A cast retainer is then bolted to theupper arm of the articulator, the anterior pin placed between thearticulator arms and bolted to the lower arm. The upper arm is layedback in an open position. A suitable amount of casting material ordental stone is piled onto the disposable cast retainer over the upperarm and the articulator is closed to embed the maxillary cast in thematerial, as shown in FIG. 5. The casting material is smoothed aroundthe sides of the cast and the articulator anterior pin is bolted to thearm thereby securing both the upper and lower arms in exact parallelrelation. The aforementioned plastic strip is wrapped around the baseand pulled tight to neatly form the mounting. During setting of thedental stone the rigid upper and lower arms secured by the anterior andposterior posts resist any expansion and thus any change of dimension.

When the casts are hardened sufficiently the anterior pin 15 is unboltedand the articulator opened and the casts removed. The impressions arethen softened and separated from the casts in a suitable manner.

FIG. 6 illustrates the manner in which the transparent teeth-settingguide is used in arranging teeth in the cast. A baseplate is fabricatedover each cast and the outer surface of the base plate is coated with asticky wax or other suitable material. For arranging teeth in the lowercast, the lower cast is mounted on the lower arm of the articulator bybolting the cast into place. The tooth-setting guide is then inserted inopening 16 in the upper arm of the articulator to the positionoriginally set. The lower surface of the toothsetting guide retains thesame vertical height as initially programmed. Usually, but notnecessarily, the mandibular teeth 32 are first set into the cast. Theteeth may be set in several ways either by attaching a roll of soft waxto the biterim with the height of the wax being short and a slightdistance below the lower surface of the transparent guide and the teethplaced consectively into the wax while it is still soft. A preferredmethod is to attach a softened cone of wax to an individual tooth andthen attach the tooth to the base plate so that the tooth is slightlyhigher than it should be. The tooth setting guide is closed against thetooth to drive it to the correct height and the articulator held closedwhile the gingival slope is adjusted. The wax is then chilled bysuitable means to hold the set tooth in the predetermined position. Oncethe mandibular teeth are set the tooth-setting guide is then removedfrom the articulator and the upper cast secured to the upper arm. Thelower cast may be removed and replaced with the transparenttooth-setting guide for the upper biterim and the two upper centrals setto the correct position using the tooth-setting guide.

Once the centrals in the upper and lower casts are positioned in placethe partially set dentures can be inserted into the patients mouth forchecking the comparative length of the mandibular and maxillary teethduring speech and repose and checking the position of the upper teeth inrelation to the lips during speech. Any modifications necessary such aschange in height of the mandibular incisors may be adjusted on thearticulator by adjusting the thumb screws on the stem of thetooth-setting guide to raise or lower the toothsetting guide to the newheight of the incisor edges. Once the centrals are set the remainder ofthe lower teeth may be set in place using the lines described on thetooth-setting guide as a guide. After these have been set thetooth-setting guide is removed from the upper arm of the articulator andreplaced with the upper cast. Then the upper teeth are arranged to fitagainst their opponents.

When the dentures have been completed the case does not need to beremounted on the articulator to refine the occlusion after processing orcasting. The original articulator mountings are preserved. The mountings35 and 40 are simply bolted back on the articulator arms and the castsattached to the mounting bases according to the indexes.

The method disclosed employing the unique toothsetting guide andarticulator offers unequalled accuracy and precision in the constructionof complete dentures or in full mouth rehabilitation.

The embodiments of the invention in which a particular property orprivilege is claimed are defined as follows:

l. A method of accurately and precisely constructing artificial denturescomprising:

1. providing biterims of the lost teeth of the patient mounted on casts,

2. orienting the biterims and casts to the occlusal plane,

3. providing a dental articulator having an upright posterior post ofrugged construction, upper and lower arms extending parallel to oneanother at substantially right angles from the upper and lower ends ofthe posterior post, the upper arm hinged to the posterior post forvertical movement, the upper and lower arms being of rugged constructionso that the vertical height between them cannot be varied by ordinaryhand pressure,

. securing the casts firmly in position to the arms of the articulatorwhile mounting to prevent accidental movement or dislodgement thereof,

. mounting the casts,

6. removing one of the mountings from an arm of the articulator,

7. securing a transparent arcuate tooth-setting guide having openings inthe body thereof over the biterim of the cast secured to thearticulator, the guide providing vision for physically arranging teethon the cast against the occlusal plane established by the guide, accessto the arranged teeth through the openings to make any corrections intheir position, and an indication of the size of the teeth to be used inconstruction, and

8. physically arranging teeth on the cast against the occlusal planeestablished by the tooth-setting guide through openings in the body ofthe guide.

2. The method of claim 1 wherein the casts are secured in step (4) by(a) securing the transparent tooth-setting guide over the biterim of thecast in a manner to prevent movement relative to the biterim eitherhorizontally or vertically and (b) securing the tooth-setting guide toeither arm of the articulator at a fixed height and in a manner toprevent rotation thereof relative to the arm.

3. The method of claim 1 including, in step (5), wrapping a flexiblestrip around the base of the mounting to neatly form the mounting.

4. A transparent tooth-setting guide including a transparent guide bodyhaving a lower surface matching the horizontal occlusal plane of apreviously formed biterim, the guide body providing clear visiontherethrough and having openings therein permitting physical arrangementof artificial teeth on the cast against the horizontal occlusal planeestablished by the guide and access to the arranged teeth to make anycorrections in their position or adjust them to premarked outer contoursof the biterim.

5. The guide of claim 4 further including spaced holes through themid-line of the guide body programmed to determine the size ofartificial teeth necessary for construction of the dentures.

6. The guide of claim 4 further including a stem rigidly attached to theguide body and extending vertically, the stem being of a form andadapted to be held by the arm of a dental articulator in a fixedposition without chance of rotation or change in vertical heightrelative to the arm of the articulator.

7. The guide of claim 6 wherein the stem is attached to the guide bodyby means permitting change in the angle of the guide body relative tothe established horizontal plane of occlusion, when necessary forcorrection of the dentures.

8. A tooth-setting guide comprising a guide body whose lower surfacematches the horizontal plane of occlusion of a previously formedbiterim, a stem extending vertically from the guide bod and meanssecuring the stem to the gui e body w 161'] allows a change in the angleof the guide body relative to the stem.

9. The guide of claim 8 wherein the means is a ball and socketconnection joint.

1. A method of accurately and precisely constructing artificial denturescomprising:
 1. providing biterims of the lost teeth of the patientmounted on casts,
 2. orienting the biterims and casts to the occlusalplane,
 3. providing a dental articulator having an upright posteriorpost of rugged construction, upper and lower arms extending parallel toone another at substantially right angles from the upper and lower endsof the posterior post, the upper arm hinged to the posterior post forvertical movement, the upper and lower arms being of rugged constructionso that the vertical height between them cannot be varied by ordinaryhand pressure,
 4. securing the casts firmly in position to the arms ofthe articulator while mounting to prevent accidental movement ordislodgement thereof,
 5. mounting the casts,
 6. removing one of themountings from an arm of the articulator,
 7. securing a transparentarcuate tooth-setting guide having openings in the body thereof over thebiterim of the cast secured to the articulator, the guide providingvision for physically arranging teeth on the cast against the occlusalplane established by the guide, access to the arranged teeth through theopenings to make any corrections in their position, and an indication ofthe size of the teeth to be used in construction, and
 8. physicallyarranging teeth on the cast against the occlusal plane established bythe tooth-setting guide through openings in the body of the guide. 2.orienting the biterims and casts to the occlusal plane,
 2. The method ofclaim 1 wherein the casts are secured in step (4) by (a) securing thetransparent tooth-setting guide over the biterim of the cast in a mannerto prevent movement relative to the biterim either horizontally orvertically and (b) securing the tooth-setting guide to either arm of thearticulator at a fixed height and in a manner to prevent rotationthereof relative to the arm.
 3. providing a dental articulator having anupright posterior post of rugged construction, upper and lower armsextending parallel to one another at substantially right angles from theupper and lower ends of the posterior post, the upper arm hinged to theposterior post for vertical movement, the upper and lower arms being ofrugged construction so that the vertical height between them cannot bevaried by ordinary hand pressure,
 3. The method of claim 1 including, instep (5), wrapping a flexible strip around the base of the mounting toneatly form the mounting.
 4. securing the casts firmly in position tothe arms of the articulator while mounting to prevent accidentalmovement or dislodgement thereof,
 4. A transparent tooth-setting guideincluding a transparent guide body having a lower surface matching thehorizontal occlusal plane of a previously formed biterim, the guide bodyproviding clear vision therethrough and having openings thereinpermitting physical arrangement of artificial teeth on the cast againstthe horizontal occlusal plane established by the guide and access to thearranged teeth to make any corrections in their position or adjust themto premarked outer contours of the biterim.
 5. The guide of claim 4further including spaced holes through the mid-line of the guide bodyprogrammed to determine the size of artificial teeth necessary forconstruction of the dentures.
 5. mounting the casts,
 6. removing one ofthe mountings from an arm of the articulator,
 6. The guide of claim 4further including a stem rigidly attached to the guide body andextending vertically, the stem being of a form and adapted to be held bythe arm of a dental articulator in a fixed position without chance ofrotation or chaNge in vertical height relative to the arm of thearticulator.
 7. The guide of claim 6 wherein the stem is attached to theguide body by means permitting change in the angle of the guide bodyrelative to the established horizontal plane of occlusion, whennecessary for correction of the dentures.
 7. securing a transparentarcuate tooth-setting guide having openings in the body thereof over thebiterim of the cast secured to the articulator, the guide providingvision for physically arranging teeth on the cast against the occlusalplane established by the guide, access to the arranged teeth through theopenings to make any corrections in their position, and an indication ofthe size of the teeth to be used in construction, and
 8. A tooth-settingguide comprising a guide body whose lower surface matches the horizontalplane of occlusion of a previously formed biterim, a stem extendingvertically from the guide body, and means securing the stem to the guidebody which allows a change in the angle of the guide body relative tothe stem.
 8. physically arranging teeth on the cast against the occlusalplane established by the tooth-setting guide through openings in thebody of the guide.
 9. The guide of claim 8 wherein the means is a balland socket connection joint.